charles mellibe



Ny PETERS, PHTDLITHOGRAPHER. WASHINGTON, D C.

UNITED STATES PATENT OFFICE.

M. A. CHARLES MELLIER, OF PARIS, FRANCE.

MAKING PAPER-PULP.

Specicaton of Letters Patent No. 17,387, dated May 26, 1857.

process for the treating of straw, and other vegetable fibrous materialsrequiring like treatment, preparatory to the use of such fibers in themanufacture of paper; and the improvement consists in subjecting strawor such other librous materials to a pressure of at least seventy poundson the square inch when boiling such fibrous matters in a solution ofcaustic alkali. For this purpose the straw or fibrous matters are cutinto short lengths, soaked in warm water and washed. They are thenplaced in a suitable boiler, and I use for such purpose a rotatoryboiler provided with a coil or coils of steam pipe for the purpose ofheating the contents; and I prefer that the boiling should be carried onat a temperature to produce at or above 80 lbs. on the square inch inthe boiler where are the brous materials to be acted upon, but so high atemperature is not absolutely necessary but I have found by experi mentthat it is essential that a temperature equivalent to seventy pounds onthe square inch must be employed. The quantity of alkali used is at therate of about 16 per cent. of caustic soda or potash of the straw orfibrous substances under process. The fibers may then be bleached by theuse of a comparatively small quantity of bleaching powder, or chlorid oflime.

To enable others skilled in the art to make and use my invention, I willproceed to describe more fully the manner of using the same.

The straw or other fibrous material requiring alike process to preparethe same for the paper manufacture, is first, as here tofore, to be cutin a chaff-cutting or other machine into short lengths, and to be freedfrom knots, dirt and dust, and then steeped for a few hours in hotwater. The straw or fibrous materials and a weak solution of causticalkali are then to be placed in a suitable closed boiler heated by steamas hereafter explained, and the heatis to be raised to such a degree asto attain and maintain for a time a pressure internally of the boilerequal to or exceeding seventy pounds on the square inch, that is about310 of Fahrenheit; by which means a considerable saving of alkali, aswell as time and fuel, results, as compared with the means of using ahot solution of caustic alkali, as now practiced in preparing straw andother bers for paper-makers.

The boiler employed for the purpose and the manner of heating it bysteam may be varied; but 1st it must have a rotatary motion either onits long or on its small axis by means which are very well known; and

Qdly I prefer not to send the steam directly.

into the liquid in which the materials are immersed, but to pass iteither in a jacket around the boiler, or through a coil or a system ofsteam pipes inside of it, so that the steam does not mix with thecaustic alkaline solution in the middle portion of the boiler, but iskept separate and does not therefore in condensing dilute the causticalkaline solution used.

The plan of construction of the boiler I would recommend would be, ifthe boiler is to rotate vertically on its small axis, as very wellknown, to cover it with a jacket so that the steam could circulate fromone end to the other between the two plates; or rather if it is torevolve horizontally or upon its long axis, as is equally very wellknown, to x near each end of the boiler, and inside of it, a diaphragmor partition, which partitions are connected together by numerous tubes,which are arranged in a circle near the outer circumference of eachpartition. By this arrangement the steam is introduced through thehollow axis at one end of the boiler, and it passes through the steampipes, and thence into the compartment at the other end of the boiler,where it and the condensed steam are conveyed away as is well understoodthrough the other hollow axis.

In adopting the plan of not sending directly the steam into the boiler Ifound the three following advantages: 1st not to dilute, as I havealready said, the alkaline solution; Qdly to avoid the trouble of havingsometimes the end of the steam-pipe in the boiler choked with straw, andto prevent, in case that by one cause or another the pressure in thesteam boiler would fall under the degree of the pressure in the strawboiler, the priming of the rst by the second, viz, the absorption ofstraw and alkaline solution from the straw boiler into the steam boiler;Bdly the greater facility of cooling the straw-boiler, when thepressurehas been maintained for a sufficient length of time, by means of turningoff the l or other fibrous materials after boiling.

By means of submitting the straw or similar fibrous material to apressure of between 70 to 84 pounds on the square inch inside of theboiler, I can reduce considerably the proportion of alkali and thesolution which I prefer to use is to be from two to Vthree degrees ofBaum or of a specific gravity of from 1.013 to 1.020, and at the rate ofabove 7 0 gallons of such solution to each cwt. of straw or otherfibrous vegetable matters requiring like treatment.

The boiler is to be filled with straw and alkaline solution and thenclosed Huid and steam tight. The boiler is made to revolve slowly, say,about one or two revolutions per minute, and the steam is to beadmitted. I find it desirable to keep up the heat and pressure duringabout three hours after the pressure above mentioned has been obtained,

Y when the process of boiling is complete. A

steam gage properly iiXed upon the boiler will enable one to ascertainwhen the pressure has attained the required degree.

When the apparatus and the fibers under process have been cooled by themeans hereinbefore mentioned or rather when the pressure has beenreduced to nothing, I open the man holes of the boiler, empty thematerials in suitable vessels, and wash them, rst with hot water, thenwith cold water, until the liquor runs perfectly clear. I then steepthe, fiber for about an hour in hot water acidulated with a quantity ofsulfuric acid equal to about 2 per cent. of the weight of the iibersunder process and nally the washing is completed with cold water. Thestraw or fiber may then be bleached in the ordinary manner and itv willbe found to be accomplished by a comparatively small quantity of chloridof lime. y

Having thus described the nature of my said invention and the manner ofperforming the same I would have it understood that I do not claim thegeneral use of caustic alkaline solutions nor the employment generallyof a close boiler for boiling straw or other vegetable fibroussubstances; Vbut What I claim as my invention and desire to secure byLetters Patent is 1. The use of a solution of caustic soda (NaO) in acompartment of a rotary vessel separate from that which contains thesteam heat substantially as described.

2. I also claim the within described process for bleaching straw,consisting in boiling it in a solution of pure caustic soda (NaO) from 2to 3 Baum, at a temperature not less than 310o Fahrenheit, after it hasbeen soaked and cleaned and before submitting it to the action of asolution of chlorid ofl lime from 1 to 1% degrees substantially asdescribed.

M. A. CHARLES MELLIER.

Vitnesses ALLERME, AMAszm.

